In 1762, the Austrian physician
Marcus Antonius von Plenciz (1705-1786) published a book titled
Opera medico-physica. It outlined a theory of contagion stating that specific 'animalculae' in the soil and the air were responsible for causing specific diseases. Von Plenciz noted the distinction between diseases which are both epidemic and contagious (like measles and dysentry), and diseases which are contagious but not epidemic (like rabies and leprosy). The book cites Anton van Leeuwenhoek to show how ubiquitous such animalculae are, and was unique for describing the presence of germs in ulcerating wounds.
But what if this amazing scientific leap
was accepted at the time? What if scientists of the 1700s and 1800s did figure out the cause of disease
rather than continuing to think it was miasma, demonic possession, "imbalanced humours", or "bad airs"?